Re: Avalon

["Gomez ADDams" <gomez-at-netherworld-dot-com> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

I forgot something:

 Interlocks.  When you're planning how the HV distribution area and controls
are laid out, you'll want to think about how you'll control access to them,
and how you'll interlock the feeds.  For instance, you might think about a
key interlock system such as Fermilab uses- in order to gain access to the
high voltage test bay (where the big coil lives), or the high voltage
transformer, or other dangerous on contact items, you have to have a key to
a door/gate in a chainlink fence or wall.  In order to get the key, you have
to open a cabinet.  When the cabinet is opened, the power feed contactor(s)
drop out.  At the gate or door, a tamper-resistant switch also drops out the
contactor(s), and lights a warning light on the safety board.  The lock on
the gate should be set up so that the key cannot be removed in the unlocked
position.  Only one person can sign out a key, and must sign it back in...

you get the idea.

Lockouts are another good idea, widely used in industry.  They are cheap
metal devices which go on disconnects or breaker handles and have a place
for up to 8 padlocks.  Each person who might be working somewhere on a large
system is assigned their own personal padlock which can be put on a single
switch. So the power to that system cannot be turned on until everyone has
removed their padlock indicating that they are "out of" the system.

 When using lockouts, have a place for each padlock near the control panels,
so that if a padlock is missing it is obvious.

 Another possible option is multiple "enable" keys on the console.  Only
keyholders are authorized to have access to the dangerous areas, and the
same key that gives access to the dangerous area must be used to enable the
control console.  If any one of the keys is not in and turned, the console
won't turn on the toys.  Obviously, you never issue more than one copy of
each key at a time, and stamp them all "do not copy"...

- Gomez,
paranoid, but still drawing breath

.........................................................................
"We cannot live only for ourselves. A thousand fibers connect us with our
fellow men; and along these fibers, as sympathetic threads, our actions
run as causes, and they come back to us as effects." -Herman Melville